Electrical switch



Au8 17, 1948 s. M. l. DE OLARIAGA ETAT. 2,447,320

' ELECTRICAL swITcH Filed July 17, 1947 3 Sheets-Shea?. 1

INVENTORS ATTORNEYS Aug. 17, 1948. s. M. l. DE OLARIAGA ETAL 2,447,320

ELEcRrcAL swITcH Filed July 17. 1947 s shane-smet 2 INVENTORS 511.11aba/zwem de O La/zw' a/ al@ @fzln/1L Aug' 17, 1948 s. M. l. DE OLARIAGAErAL 2,447,320

ELECTRICAL SWITCH 3 Sheets-Sheet 3 Filed July 17, 1947 Patented ug. 17,1948 ELECTRICAL SWITCH Sara Maria Iribarren de Olaraga, Luis Bulgarini,and Percy-Forster, Buenos Aires, Argentina Appiieation'auly 17,1947,'seria1Ne. 761,542

` In Argentina May 22, 1947 Claims. 1

This invention relates to an electrical switch of simple and durableconstruction, and highly reliable in operation.

One of the objects of the present invention is to provide an electricalswitch having the desirable characteristics of rapidly closing andopening the circuit, thus avoiding bad connections and arcingat thecontacts.

Another object is to provide a switch in which the contact bridge, whenin the inoperative position, is positively incapable of accidentallyestablishing contact with the associated resilient con- -tact members,owing to the fact that it is firmly maintained in a definite inoperativeposition, and in addition, the points of engagement between saidcontactmembers and the contact bridge are so arranged that electrical`contact between them is impossible.

The new electrical switchincludes two resilient conducting 'armsarranged .in pincer fashion and adapted to retain inits operativeposition a movable :bridging conductive member, represented by a ball,roller or thelike, capable of passing from the operative 'to theinoperative position due to the thrust effect of means operated from theoutside and 'under the resilient action of said electrical conductingmeansy the switch according to this invention being furthercharacterized -by the fact that the two conducting -arms arranged inpincer fashion have curved portions inter-mediateof their length,adapted to cooperatively receive and retain the movable bridging member,one vof the pincer arms being provided with an end extension thatvcontinues from the associated curved portion and is so shaped as vtofacilitate the release and the entrance of the bridging member, whilethe-other res'ilient'pncer arm Vhas a bent resilient-extension the freeend of which -is arranged at such a distance tothe nearest 'part'ofthecurved seating portion of the same arm, 'that the movable bridge iscapable of moving from said curved portion to the free end without4breaking contact with the conducting arm, an insulating shoe beingmounted on the above mentioned free end of the bent resilient extensionand'which, when the Contact bridge is in operative position, remainsnormally interposed `between vthe conducting portions of the related armand the other 'conducting arm, thus irripeding the access of the contactbridge to the conductive lpincer, said shoe having in addition a contactedge vor face opposite to a corresponding portion of the other member,to form with said portion, a resilient impulsion eouplewhich tends toforce the contact bridge Atowards the inside of the pincer, during theoperative stroke of said bridge.

Other objects 'and advantages `of the invention will become apparent tothose skilled inthe art, from the following description taken inconjunction with the accompanying drawings illustrating a preferredembodiment of the invention fand wherein:

Fig. l is an external perspective View of a single-pole wall switch.

Fig. `2 Vis another perspective but of a 'section-of thesame switch ofFig. 1, the Contact Ybridge being in its operative position, betweenVthearrns of the pincer.

Fig. 3 is a lateral elevation and longitudinal section of the sameswitch, the'contactbridge be.- ing shown still in its operative positionibetween the arms of the .pincen but .just about'to be ejected from thearms of the pincel?, in order to open the circuit.

I`Fig. 4 is similar to Fig. 3, but in which 'the movable contact bridgeis in its inoperative posi.- ti'on, and makes contact with only one ofthe conducting portons of the resilientarms of the'pincer, so that 'thecircuit in which the switch is interposed will lremain open.

Fig. l5 is a perspective View of `a three-pole switch, in which, tosimplify the drawing, some parts have been eliminated, for instance thecover and the main base.

Fig. '6 is a side elevation and sectional View of a switch of the typeof Fietb7 but without eliminating'the above mentioned parts.

lThe same reference characters are used 'to in.- dicate like orcorresponding parts or elements throughout'the drawings.

In accordance with that illustrated in Figs. 1 to 4, corresponding to asingle-pole switch, a is an external box in the shape of a prism havingirregular hexagonal bases which are indicated with the numerals l, I.'One of the side faces is removable for access to the interior of theswitch, while the largest side 2 constitutes the front of the box. Whenthe box is embedded in theca'vity of a wall, the sides 3 and 'l of thesame box form respectively the upper and lower base. The remainingsides, 4, 5 and 6 form the back Wall v.ofthe box. The holes 8, formed inthe front -2 and walls 4 and 6, are used for attaching Vthe box, 4and'consequently the switch, tothe corresponding wall cavity, in which theusual metal fittings must be provided forthe mounting screws adaptedtofgrip the box a through the holes 8.

The construction of the outer box a is completed with a rectangularwindow 9, formed .in the front wall 2 and adapted, as will be shownlater, to receive the operating handle of the switch.

Within the bor: a is provided a movable body b generally shaped as a'prism of hexagonal base, similar to a, but smaller and without thebases that would correspond to the surfaces I and I' of the box a. Asrmay be seen in Figs 2 to 4, the inner movable body b, which has a frontI0, two bases Il and l2 and three rear faces I3, 'I4 and be displacedwithin the box by means of the r handle l 6 projecting out of the box athro-ugh the window 9. It should be understood that the window 9 mustpreferably be of such dimensions as to provide only suiiicient space forthe passage and necessary movement of said handle, thus serving as aguide and movement limiting means for said handle. Thus, it will be alsoobserved that the outer box a being only opened at its window portion 9,and the front l) being applied directly against the inner face 2 of thebox a, the interior of the switch, and consequently all the insideelements will be protected from dust.

-1 The side wall l of the box a is provided with two interiorlyprojecting supports Il and I8 which are disposed within the movable bodyb. On these supports there are fixed by means of the correspondingscrews l 9 the resilient arms c and d arranged face to face, as shown inFigs. 2, 3, and Zi. The conducting wires e may also be affixed to thesescrews. The two resilient arms are made of metal sheet having a highelectrical conductivity and are shaped according to the interruptedsinusoidal form as illustrated, both having curved intermediate portions20 and 2l, so dimensioned as to form cooperating retaining seats for themovable bridging member f, also made of conducting material. This memberis represented as a cylinder, although it will be apparent that it maybe in the form of a spherical ball or any other body having a suitablycurved surface. The movable member f has as lateral guides the walls land I of the boi.r a, spaced apart at a distance slightly greater thanthe length of said member. The two above mentioned resilient arms, dueto their constructive and operational characteristics, constitute a formof retaining pincer for the bridging member f. Beyond its curved seatportion 2l, the arm d is provided with a slightly curved short extension22, adapted to serve as a point for the ejection or entrance of theroller constituting the movable contact bridge.

Referring now to the resilient arm c this is also provided with anextension formed beyond the intermediate seat portion 20. Unlike the armd, the end extension 23 of the arm c is bent in the form of a U, the twolegs of which face towards the other resilient arm. The leg 23', whichis the farthest spaced from the intermediate curved seat 20 is locatedat such a ydistance from such seat that the roller f when beingdisplaced towards said leg 23 engages said leg before leaving its seat,whereby the continuity of connection between the two arms is notinterrupted. The leg 23' is so proportioned and disposed that its freeend, which may be provided with a slightly widened portion 23" in orderto offer a greater contact surface to the roller f, faces the extension22 of the'arm d, and is spaced at such a distance from the extension 22of the arm d that the roller fis gripped in a pincer-like fashion whenmoving from the extreme operative position of Fig. 2 to the intermediateposition of Fig. 3.

In the free leg 23 of the U-shaped bend 23 which also includes theslightly widened portion 23, there is loosely mounted an insulating shoeg, which has an arm 24 terminating in a bend 22', which, as shown inFig. 2, cooperates with the leg of the U-shape-d bend locatedimmediately beyond the seat 20 of the arm c. In this way, the

4 bend 2t partially surrounds the aforementioned leg of the arm c inorder to limit indirectly the movements of the other ypreviouslymentioned leg 23'; This ensures that the'leg 23 will be alwaysmaintained at a minimum distance from the seat 20, thus providing forthe electrical continuity of the connection between the arms c and dwhen the roller f moves away from the seats 2B and 2l. A part of thecontour of the shoe g is curve shaped similarly to the outer surface ofthe roller f, so that it fits firmly over said roller, as shown in Fig.fl. Between the portion 25 and `the leg 23 of the bend 23 is a shortstraight porthe inoperative position.

tion 26, against which the roller f bears initially when being insertedbetween the arms c and d of the conducting pincers so that the rollerisheld between the non-conducting portion 26 vof the shoe and the endextension 22 of arm d, which; due to its spring tension is capable ofsnapping the conducting roller into the pincers at the ap-v propriatetime.

It will be seen from Figs. 2, 3 and 4, that the switch, as described, isprovided with two stops 2l integral with the side wall i 'of box a andadapted to maintain the roller f in its inoperative position, andlimiting its spacing from the seats 2b and 2l of the pincers (Fig. 4).There are also provided two otherstops 28 and 28 which are movable andserve as means for moving the roller member employed as the connectingbridge element of the switch. These two stops 28 and 28' are formed inor Jfitted in line with but opposite each other on the interior walls ofthe inside movable body having been arranged oppositely and on the sameline at the side walls b and are positioned so as to engage the bridgingroller at two diametrally opposed points, and to pass between the armsof the conducting pincers when moved to and from the extreme positionsillustrated in Figs. 2 and 4 respectively. l

From the foregoing, it will be seen that in the embodiment illustratedby Figs. 1 to 4, the movable contactbridge represented by the hollowmetal roller, is subject at all times to the action of the conductingarms c and d, arranged in pincer like fashion. The arms do not however,act by themselves, but their action is assisted by the movable stops 28and 28', which in turn are actuated externally at will by means of thehandle The effect, the movable stops 28 and 2W represent the means,controlled by the user of the switch, by which movement of the contactbridge is initiated in order to place it in the operative or Thesestops, however, are not capable of controlling the moving bridge in thelast stage of its displacement, which takes lplace under the action ofthe arms c and d of the spring pincers and which are completely outsidethe control of the operator. This detail is of the utmost importance,lsince il; ensures the completion of the final part of the displacementof the bridging roller, independently of the operator of the switch, whois therefore prevented from incorrectly operating the bridge and thuscausing, either deliberately or accidentally, false contacts when thebridge is introduced or withdrawn from between thearms of the pincers.

Thus, when the bridge f is in the operative position as shown in Fig. 2in which it is gripped between the two cooperating seats 29 and 2| ofthe arms c and d for closing the electric circuit of the switch, it isnecessary, in order to move the bridge to the inoperative open circuitposition as shown in Fig. 4, to.cause the internal 5 movable body b tomove downwards by moving the handle I6 in the same direction. Themovable stop 28 then advances towards the bridge f and the stop 28'moves away from it as the other stop advances. As the bridge moves awayfrom the seats 20 and 2|, the arms c and d of the resilient pincers opensuiiciently to allow of the passage of the bridging roller. During itsmovement, the latter roller reaches the position shown in Fig. 3, inwhich position it has practically left the seats in which it wasretained, and is actually tightly pressed by the two arms of the pincer;and is just about to be ejected at an even greater distance from saidseats. It should be noted that in said intermediate position in whichthe bridge is still engaging the arms of the pincer, the roller f isalso engaging the free end 23 of the U extension of the arm c; i. e., itmaintains a double Contact with said arm. rIhis is important since, asthe ejection of the roller to the inoperative position of Fig. 4 mustoccur under the pressure of the free end of the bend 23 and the oppositeangular portion of the other arm of the pincer, it is necessary thatuntil said ejection is effected the roller is maintained in contact withboth arms of the pincer. If, in passing from its position between theseats 2li and 2| to the position in which it engages the free end of thebend 23, the roller f were to become momentarily disengaged from the armc (at this stage of its movement, the roller is controllable fromoutside), it would be possible to produce a slow breaking of the contactbetween both parts, with the consequent detrimental results.

As soon as the movable stop 28 advances a little farther, the twopartsof the resilient pincer that press rmly on the curved surface of theroller, begin to slip along said surface, in a natural and independentclosing movement, due

to spring action, and by pinching the roller,

sharply eject it against the stops 21. This breaks the contact between cand d, and leaves the roller rmly held against the stops 21, on accountof the fact that the arms of the pincer continue their movement andclose behind the roller. The latter is thus retained between the stops21, the shoe g and the end extension 22 of the arm d, as shown in Fig.4. The movable stop 28, however, is made of such a length that it doesnot advance beyond the position reached when the two arms of theresilient pincer start the pinching action on the roller.

To reclose the circuit, by restoring the bridging roller to the initialposition as shown in Fig. 2, the handle I5 is operated in the reversedirection to raise the inner movable body. Thus the movable stop 28approaches the contact roller, and the stop 28 moves away from it. Whenthe stop 28 engages the roller f and commences to force it between thecontact pincers, the arms c and d of said pincer open but maintaincontact with the roller, on account of their elasticity. At the initialstage of the movement of the roller, it engages the conducting position22 of the arm d and the non-conducting shoe o-f the arm c, and thus thetwo arms are not electrically connected. In yielding to the action ofthe roller, the shoe moves to the left until its rectilinear contourportion 2G is applied against the curved surface of the roller and thediametrally o-pposed part of the roller is engaged by a portion of thearm d corresponding to its end extension 22 or to the ridge separatingsaid part from the seat 2|. Although the roller makes contact with theportion 26 of the shoe g, it does not enter into contact with the 'freeend of the'branch 23 of the bend 23 ofthe arm c. In continuing themovement ofthe stop 28', when the roller f is in a position verysimilar, although not equal, to that shown in Fig. 3, said roller,without engaging at any moment the free end of the branch 23', issharply ejected, also by a pinching .action of the two pincer arms,towards the seats 20 and 2| of said pincer, thus producing electricalcontact between the two arms, and the resulting closing of the circuit.The resilient arms of the pincer follow the movement of 'the roller andare instantaneously applied at both sides of the roller, the wholeassembly assuming the position shown in Fig. 2.

The three-pole switch of Figs. 5 and 6 is essentially a multiplicationof the above described single pole switch. The three pairs of resilientarms c' with shoes g and d are substantially similar to thecorresponding elements c and d of the other switch and operate in likemanner and similar conductor rollers f are also used. The arms c and d'are firmly attached by means of screws 29 against the inner face of thevertical plate 3B. This vplate is in turn attached to the intermediatebase plate 3|, which is maintained in a raised position over theprincipal base 32, by means of the bolts 33. For the external operationof the rollers f' there is provided a sliding member h, made ofinsulating material and comprising, as may be seen in Fig. 5, a plate 34with an internal opening 35 which allows of the formation of the movablestops 3S and 3B' adapted to move the respective rollers, and of thelarge recesses 3? adapted to operate as guides for the plate 34 itselfand as means for limiting its displacement. The small vertical stop andguide partitions 38 cooperate with the sliding member h and are adaptedto assist in the guiding of the sliding member h, to limit the extent ofthe movei; ment of said member, and to maintain the bridging rollers fin their lateral position. The sliding member h is provided With ahandle 39 attached at its fore end and is arranged horizontally betweenthe arms of the cooperating resilient conducting pincers, beingmaintained in correct position and free for longitudinal movement bymeans of two lateral guiding supports 4U attached with screws 4| to thebase plate 3|.

The conducting wires e' are connected directly to the terminals 29'(Fig. 6) formed by nuts threaded on to the ends of the screws 29 whichare used to attach the arms c and d to the support 3U.

The operation of the three pole switch is substantially similar to theoperation of the single pole switch previously described with referenceto Figs. 1 to 4, as all the essential elements are practically the same.Thus, when the sliding member h. is moved by pulling the handle 29, themovable stops 35 simultaneously start to move vthe rollers f' away fromthe seats of the resilient pincers. Each of the rollers is then swiftlyejected in the manner described, above, and remain gripped in theinoperative position (open circuit), between the cooperating stop 36,the conducting end of the arm d and the insulating shoe g'. By movingthe insulating sliding member h in the reverse direction, the rollersmay be replaced as in the case of the single pole switch to theiroperative closed circuit positions. In this way, it is possible toobtain a sure and simultaneous opening or closing of the circuit in eachone of the three pincer units of the switch.

It will be clear that in carrying the present invention into practice,modications may be made as regards certain details of the constructionof the electrical switch described, but always provided that suchmodifications do not depart from the fundamental principles which areclearly set forth in the accompanying claims.

We claim:

1. An electrical switch including two resilient conductive arms arrangedin pincer like fashi-on and adapted to retain in its operative positiona movable conductive bridging member represented by a roller, ball orthe like capable of passing from the operative to the inoperativeposition or vice versa by a thrust action of externally actuated meansandy by the resilient effect of said electrically conductive arms,wherein the two conductive arms arranged in pincer like fashion areprovided at their respective intermediate portions with oppositelycurved seating sections, adapted to cooperatively receive and retain themovable bridging member, one of the pincer arms having an end extensionthat continues from the associated curved portion and is so shaped as tofacilitate the release and the entrance of the bridging member, whilethe other resilient pincer arm has a bent resilient extension the freeend of which is arranged at such a distance from the nearest partl ofthe curved seating portion of the same arm, that the movable bridge iscapable of moving from said curved portion to the free end withoutbreaking its contact with the conductive arm, an insulating shoe beingmounted on the above mentioned free end of the resilient bent extensionand which, when the contact bridge is in operative position, remainsnormally interposed between the conducting portions of the related armand the other conductive arm, thus blocking the access of the contactbridge to the conductive pincer, said shoe having in addition a contactzone facing an associated portion of the other member, to form with saidportion a resilient pair for impulsion of the contact bridge towards theinside of the pincer, during the operative stroke of said bridge.

2. An electrical switch including two resilient conductive arms arrangedin pincer like fashion and adapted to retain in its operative position amovable conductive bridging member represented by a roller, ball or thelike capable of passing from the operative to the inoperative positionor vice versa by a thrust action effected by -externally actuated meansand by the resilient effect of said electrically conductive arms,wherein the two conductive arms arranged in pincer` like fashion areprovided at their respective intermediate portions with oppositelycurved seating sections, adapted to cooperatively receive and retain themovable bridging member, one of the pincer arms having an end extensionthat continues from the associated curved section and is so shaped as tofacilitate the release and the entrance of the bridging member, Whilethe other resilient pincer arm has an extension bent in the' form of a Uwith the legs of the U looking facing towards the rst pincer arm andwith the free ing arm, thus blocking the access of the contact bridge tothe conductive pincer, said shoe having in addition a contact zonefacing an associated portion of the other member, to form with saidportion a resilient pair for the impulsion of the contact bridge towardsthe inside of the pincer, during the operative stroke of said bridge.

3. An electrical switch including two resilient conductive arms arrangedin pincer like fashion and adapted to retain in its operative position amovable conductive bridging member represented by a roller, ball or thelike capable of passing from the operative to the inoperative positionor vice versa by the thrust action of externally actuated means and bythe resilient eifect of said electrically conductive arms, wherein thetwo conductive arms arranged in pincer like fashion are provided attheir respective intermediate portions with oppositely curved seatingportions, adapted to cooperatively receive and retain the movablebridging member, one of the pincer arms having an end extension thatcontinues from the associated curved portion and is so shaped as tofacilitate the release and the entrance of the bridging member, whilethe other resilient pincer arm has a bent resilient extension, the freeend of which is arranged at such a distance from the nearest part of thecurved seating portion of the same arm that the movable bridge is.capable of moving past said curved portion of the free end Iwithoutbreaking contact with the vconductive arm, an insulating shoe beingmounted on the above mentioned free end of the resilient bent extensionwhich when the contact bridge is in its operative position, remainsnormally interposed between the conducting portions of the related armand the other conductive arm, thus blocking the access of the contactbridge to the conductive pincer, said shoe having a curved portionadapted to engage the curved surface of the contact` bridge, a small,preferably straight, portion being disposed adjacent to said curvedportion to form the contact zone and adapted to engage said contactbridge only during the movement of said bridge from the inoperative tothe operative position in order to form the resilient pair for theoperative impulsion of said bridge.

4. An electrical switch including two resilient conductive arms arrangedin pincer like fashion and adapted to retain in its operative position amovable conductive bridging member represented by a roller, ball or thelike capable of passing from the operative to the inoperative positionor vice versa by the thrust action of externally actuated means and bythe resilient effect of said electrically conductive arms, wherein thetwo conductive arms arranged in pincer like fashion are provided attheir respective intermediate portions with oppositely curved seatingporti-ons, adapted to cooperatively receive and retain the movablebridging member, one of the pincer arms having an end extension thatcontinues from the associated curved portion and is so shaped as tofacilitate the release an-d entrance of the bridging member, while theother resilient pincer arm has a bent resilient extension, the free endof which is arranged at such a distance from the nearest part of thecurved seating portion of the same arm, that the movable bridge iscapable of moving past said curved portion of the free end withoutbreaking its contact with the conductive arm. an insulating shoe beingi'lxedly attached to the branch of the bent portion of the correspondingresilient arm which is more remote from the curved seating portion, andprovided with an arm engaging the other branch` of the bent portion forlimiting the spacing between said tw'o branches, said shoe being adaptedwhen the contact bridge is in its operative position to remain normallyinterposed between the conductive portions of the related arm and theother conductive arm, and having in addition a contact zone facing anassociated portion of the other member, to Iform with said portion aresilient pair for the impulsion of the contact bridge towards theinside of the pincer, during the operative stroke oi said bridge.

5. An electrical switch including two resilient conductive arms arrangedin pincer like fashion and adapted to retain in its operative position amovable conductive bridging member represented by a roller, ball or thelike capable of passing from the operative to the inoperative positionor vice versa by thev thrust action of externally actuated means and bythe resilient effect of said electrically conductive arms, wherein thetwo conductive arms arranged in pincer like fashion are provided attheir respective intermediate portions with oppositely curved seatingportions, adapted to cooperatively receive and retain the movablebridging member, one of the pincer arms having an end extension thatcontinues from the associated curved portion and is so shaped as tofacilitate the release and entrance of the bridging member, while theother resilient pincer arm has a bent resilient extension the free endof which is arranged at such a distance from the nearest part of thecurved seating portion of the same arm, that the movable bridge iscapable of moving past said curved portion of the free end withoutbreaking its contact with the conductive arm, an insulated shoe beingmounted on the above mentioned free end of the resilient bent extensionwhich when the contact bridge is in the operative position, remainsnormally inl terposed between the conducting portions or the related armand the other conductive arm thus blocking the -access f the contactbridge to the conductive pincer, said shoe having in addition a contactzone slightly more protruding than the most advanced portion of the freeend of the conductive bent portion of said pincer arm and facing anassociated portion of the other member, to form with said portion aresilient pair for the impulsion of the contact bridge towards theinside of the pincer during the `operative stroke of said bridge.

6. An electrical switch including two resilient conductive arms arrangedin pincer like fashion and adapted to retain in its operative position amovable Conducting bridging member represented by a roller, ball or thelike, said conductive resilient arms being iixed to one of the sidewalls of an external box having a second side wall substantiallyparallel to the first mentioned side wall to guide the movable contactbridge and to guide an internal sliding body having movable stopsadapted to move said movable bridge in cooperation with the resilientaction of said electrically conductive arms either to the operative orto the inoperative position of said body, wherein the two lconductivearms arranged in pincer like fashion are provided at their respectiveintermediate portions with oppositely curved seating sections, adaptedto cooperatively receive and retain the movable bridging member, one ofthe pincer arms having an end extension that continues from theassociated curved portion and is so shaped as to facilitate the releaseand the entrance of the bridging member, while the other resilientpincer arm has' a bent resilient exten.- sion the free end of which isarranged at such a distance'from the nearest part of' the curved seatingportion' of the same arm, that the movable bridge is capable'ofmoving'from said curved portion to the free end without breaking itscon'- tact with the conductivearm, an insulating shoe being mounted onthe above mentioned free end of the resilient bent extension and which,when the Contact bridge is in operative position, remains normallyinterposed between'the conducting portions Iof the related arm and theother conductive arm, thus blocking the access of the contact lbridge tothe conductive pincer, said shoe having in addition a contact zonefacing an associated portion ofy the other member, to form with saidportion a resilient pair for impulsion of the Contact bridge towards theinside of the' pincer, during the operative stroke of said bridge.

7. An electrical switch including two resilient conductive arms arrangedin pincer like fashion'` and adapted to retain in its operative positiona movable conductive bridging member repre,- sented by a roller, ball orthe like capable of pass-l ing from the operative to the inoperativeposi,- tion or vice versa, said conductive resilient arms being fixed tolone of the sidewalls of an external box shaped as an orthogonalprismhaving polygonal bases with said bases constituting the sides ofthe box and one of the side wallsV forming the front of the box, anopening in the front wall adapted to accommodate, and serve as a guidemeans, for the operating handle of the switch', said handle being xed tothe front wall of an internal sliding body having movable stops adapt'-ed to move said movable bridge, in cooperation with the resilient actionof said electrically conductive arms, either to the operative or to thevin-` operative position ofV said body, and said front wall of saidinternal sliding body being slidingly applied against the inner face ofthe front walll ofthe external box, wherein the arms arranged in pincerlike fashion are provided at their respective intermediate portions withoppositely curved seating sections, adapted to cooperatively receive andretain the movable bridging member, one of the pincer arms having an endextension that continues from the asso-` ciated curved portion and is soshaped as tofacilitate the release and the entrance of the bridgingmember, while the other resilient pincer arm has a bent resilientextension the free end of which is arranged at such a distance from thenearest part of the curved seating portion of the same arm, that themovable bridge is capable of moving from said curved portion to the freeend without breaking its contact with the conductivev arm, an insulatingshoe being mounted on the above mentioned freev end of the resilientbentr extension and which, whenI the contact bridge is in operativeposition, remains normally 1nterposed between the conducting portions ofthe related arm and the other conductive arm, thus blocking the accessof the contact bridge to the conductive pincer, said shoe having inadditionl contact Zone facingan associated portion of the other member,to form with said portion Va resilient pair forimpulsionof the contactbridge towards the inside of the pincer, during the op`v erative strokeof said bridge.

8. In an electrical switch, a plurality of electrical switching units,each unit including two resilient conductive arms arranged in pincerlike' fashion and adapted to retain in its operative position 'a movableconductive two conductive bridging member 11 represented by a roller,ball or the like capable of passing from the operative to theinoperative position or vice versa by the thrust action of opposingprojections formed in the cut out portion of a sliding plate adapted tobe displaced relatively to said bridges, said cut out portion beingprovided with pairs of respectively opposed notches adapted to cooperatewith small guiding partitions located at the sides of and adapted toguide the respective bridges, wherein the two conductive arms arrangedin pincer like fashion of each switching unit are provided at theirrespective intermediate portions with oppositely curved seatingportions, adapted to cooperatively receive and retain the relatedmovable bridging member, one of the pincer arms of each unit having anend extension that continues from the associated curved portion and isso shaped as to facilitate the release and entrance of the bridgingmember, while the other resilient pincer arm of the same unit has a bentresilient extension the free end of which is arranged at such a distancefrom the nearest part of the curved seating portion of the same arm,that the movable bridge is capable of moving past said curved portion ofthe free end without breaking its contact with the conductive arm, aninsulating shoe being mounted on the above mentioned free end of theresilient bent extension which when the contact bridge is in itsoperative position, remains normally interposed between the conductingportions of the related arm and the other conductive arm, thus blockingthe access of the contact bridge to the conductive pincer, said shoehaving in addition a contact Zone facing an associated portion of theother member, to form with said portion a resilient pair for theimpulsion of the contact bridge towards the inside of the pincer, duringthe operative stroke of said bridge.

9. In an electrical switch, a plurality of electrical switching units,each unit including two resilient conductive arms arranged in pincerlike fashion and adapted to retain in its operative position a movableconductive bridging member represented by a roller, ball or the likecapable of passing from the operative to the inoperative position orvice versa by the thrust action of opposing projections formed in thecut out portion of a sliding plate adapted to be displaced relatively tosaid bridges, said cut out portion being provided with pairs ofrespectively opposed notches adaptedy to cooperate with small guidingpartitions located at the sides of and adapted-to guide the respectivebridges, wherein the two conductive arms arranged in pincer like fashionof each switching unit are provided at their respective intermediateportions with oppositely curved seating portions, adapted tooooperatively receive and retain the related movable bridging member,one of the pincer arms of each unit having an end extension thatcontinues from the associated curved portion and is so shaped as tofacilitate the release and entrance of the bridging member, while theother resilient pincer arm of the same unit has a bent resilienteXtensionthe free end of which is arranged at such a distance from thenearest part of the curved seating portion of the same arm, that themovable bridge is capable of moving past said curved portion of thefreev end without breaking its Contact with the conductive arm, aninsulating shoe being mounted on the above mentioned free end of theresilient bent extension which when the contact bridge is in itsoperative position, remains normally interposed between the conductingportions of the related arm and the other conductive arm, thus blockingthe access of the contact bridge to the conductive pincer, said shoehaving in addition a contact zone facing an associated portion of theother member, to form with said portion a resilient pair for theimpulsion of the contact bridge towards the inside of the pincer, duringthe operative stroke of said bridge, said sliding plate being slidinglymounted in parallel relationship with an intermediate base plate whichin turn is xedly mounted at a distance from a main base plate, thepincer arms being firmly attached to a. vertical partition.

l0. In an electrical switch, a plurality of electrical switching units,each unit including two resilient conductive arms arranged in pincerlike fashion and adapted to retain in its operative position a movableconductive bridging member represented by a roller, 'ball or the likecapable of passing from the operative to the inoperative position orvice versa by the thrust action of opposing projections formed in thecut out portion of a sliding plate adapted to be displaced relatively tosaid bridges, said cut out portion being provided with pairs ofrespectively opposed notches adapted to cooperate with small guidingpartitions located at the sides of and adapted to guide the respectivebridges, wherein the two conductive arms arranged in pincer like fashionof each switching unit are provided at their respective intermediateportions with oppositely curved seating portions, adapted tocooperatively receive and retain the related movable bridging member,one of the pincer arms of each unit having an end extension thatcontinues from the associated curved portion and is so shaped as tofacilitate the release and entrance of the bridging member, while thevother resilient pincer arm of the same unit has a bent resilientextension the free end of which is arranged at such a distance from thenearest part of the curved seating portion of the same arm, that themovable bridge is capable of moving past said curved portion of the freeend without breaking its contact with the conductive arm, an insulatingshoe being mounted on the above mentioned free end of the resilient bentextension which when the contact bridge is in its operative position,remains normally interposed between the conducting portions of therelated arm and the other conductive arm, thus blocking the access ofthe contact bridge to the conductive pincer, said shoe having inaddition a contact Zone facing an associated portion of the othermember, to form with said portion a resilient pair for the impulsion ofthe contact bridge towards the inside of the pincer, during theoperative stroke of said bridge, said sliding plate being slidinglymounted in parallel relationship with an intermediate base plate whichin turn is iixedly mounted at a distance from a main base plate, thepincer arms being firmly attached to a vertical partition, and a coverbeing provided to protect the essential elements of the switch, ttedover the main base plate and provided with an aperture in its front forthe passage of a handle adapted to operate the sliding plate from theoutside of said boX.

SARA MARIA IRIBARREN DE OLARIAGA.

LUIS BULGARINI.

PERCY FORSTER.

